Linux互斥锁的使用代码实现

最新推荐文章于 2025-10-23 16:37:59 发布

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#linux #buffer #fun #null #join #include

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本文通过两个线程交替修改全局变量的例子演示了如何使用互斥锁来保护临界区，防止数据竞争，展示了互斥锁开启和关闭时程序的不同行为。

#include <stdio.h>
#include <pthread.h>
#include <sched.h>
#include <unistd.h>

//对临界区的保护问题

void *fun1(void *arg);
void *fun2(void *arg);

int buffer = 0;
pthread_mutex_t mutex;
int running = 1;

int main(void )
{
    pthread_t pt1;
    pthread_t pt2;

    pthread_mutex_init(&mutex,NULL);

    pthread_create(&pt1,NULL,fun1,(void*)&running);
    pthread_create(&pt2,NULL,fun2,(void*)&running);

    usleep(1000);
    running=0;
    pthread_join(pt1,NULL);
    pthread_join(pt2,NULL);
    pthread_mutex_destroy(&mutex);
    return 0;
}

void *fun1(void *arg)
{
    while(*(int *)arg)
    {
        //pthread_mutex_lock(&mutex);
	pthread_mutex_lock(&mutex);
        printf("in fun1 before add , buffer is : %d\n",buffer);
        usleep(2);
        buffer++;
        printf("in fun1 after sleep and add one ,now buffer is %d \n",buffer);
        //pthread_mutex_unlock(&mutex);
	pthread_mutex_unlock(&mutex);
        usleep(2);
    }
}

void *fun2(void *arg)
{
    while(*(int *)arg)
    {
        //pthread_mutex_lock(&mutex);
	pthread_mutex_lock(&mutex);
        printf("in fun2 before add , buffer is : %d\n",buffer);
        usleep(2);
        buffer++;
        printf("in fun2 after sleep and add one ,now buffer is %d \n",buffer);
        //pthread_mutex_unlock(&mutex);
	pthread_mutex_unlock(&mutex);
        usleep(2);
    }

}

注释互斥锁前的运行结果：